Experimental Data Snapshot

  • Resolution: 1.67 Å
  • R-Value Work: 0.182 

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Extensive features of tight oligosaccharide binding revealed in high-resolution structures of the maltodextrin transport/chemosensory receptor.

Quiocho, F.A.Spurlino, J.C.Rodseth, L.E.

(1997) Structure 5: 997-1015

  • DOI: https://doi.org/10.1016/s0969-2126(97)00253-0
  • Primary Citation of Related Structures:  
    1ANF, 3MBP, 4MBP

  • PubMed Abstract: 

    Active-transport processes perform a vital function in the life of a cell, maintaining cell homeostasis and allowing access of nutrients. Maltodextrin/maltose-binding protein (MBP; M(r) = 40k) is a receptor protein which serves as an initial high-affinity binding component of the active-transport system of maltooligosaccharides in bacteria. MBP also participates in chemotaxis towards maltooligosaccharides. The interaction between MBP and specific cytoplasmic membrane proteins initiates either active transport or chemotaxis. In order to gain new understanding of the function of MBP, especially its versatility in binding different linear and cyclic oligosaccharides with similar affinities, we have undertaken high-resolution X-ray analysis of three oligosaccharide-bound structures. The structures of MBP complexed with maltose, maltotriose and maltotetraose have been refined to high resolutions (1.67 to 1.8 A). These structures provide details at the atomic level of many features of oligosaccharide binding. The structures reveal differences between buried and surface binding sites and show the importance of hydrogen bonds and van der Waals interactions, especially those resulting from aromatic residue stacking. Insights are provided into the structural plasticity of the protein, the binding affinity and the binding specificity with respect to alpha/beta anomeric preference and oligosaccharide length. In addition, the structures demonstrate the different conformations that can be adopted by the oligosaccharide within the complex. MBP has a two-domain structure joined by a hinge-bending region which contains the substrate-binding groove. The bound maltooligosaccharides have a ribbon-like structure: the edges of the ribbon are occupied by polar hydroxyl groups and the flat surfaces are composed of nonpolar patches of the sugar ring faces. The polar groups and nonpolar patches are heavily involved in forming hydrogen bonds and van der Waals contacts, respectively, with complimentary residues in the groove. Hinge-bending between the two domains enables the participation of both domains in the binding and sequestering of the oligosaccharides. Changes in the subtle contours of the binding site allow binding of maltodextrins of varying length with similarly high affinities. The fact that the three bound structures are essentially identical ensures productive interaction with the oligomeric membrane proteins, which are distinct for transport and chemotaxis.

  • Organizational Affiliation

    Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA. faq@dino.bcm.tmc.edu

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
MALTODEXTRIN-BINDING PROTEIN370Escherichia coli K-12Mutation(s): 0 
Gene Names: MALE
Find proteins for P0AEX9 (Escherichia coli (strain K12))
Explore P0AEX9 
Go to UniProtKB:  P0AEX9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0AEX9
Sequence Annotations
  • Reference Sequence


Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
Glycosylation Resources
GlyTouCan:  G07411ON
GlyCosmos:  G07411ON
Biologically Interesting Molecules (External Reference) 1 Unique
Entity ID: 2
IDChains NameType/Class2D Diagram3D Interactions
Query on PRD_900001
alpha-maltoseOligosaccharide / Nutrient
Experimental Data & Validation

Experimental Data

  • Resolution: 1.67 Å
  • R-Value Work: 0.182 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 105.88α = 90
b = 68.44β = 112.54
c = 57.94γ = 90
Software Package:
Software NamePurpose
PROTEINmodel building
CHAINmodel building
SDMSdata reduction
SDMSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1997-12-24
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Source and taxonomy, Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Other, Structure summary
  • Version 2.1: 2023-08-02
    Changes: Database references, Refinement description, Structure summary
  • Version 2.2: 2024-05-22
    Changes: Data collection